Electric energy is the most widely and conveniently used energy among all the kinds of energy available to human beings. With quickening of global energy consumption, promotion of electric energy utilization efficiency, specially working efficiency of electric and electronic conversion power supply, has been increasingly gained attention. As an entrance power supply of electric equipment, its efficiency greatly influences the total efficiency of the equipment, and if the efficiency of exit and entrance power supply conversion cannot be improved, the total electric energy efficiency of the equipment can only be less than, instead of higher than, the efficiency of exit and entrance power supply conversion.
FIG. 1 shows an topological circuit application solution of a mainstream three-phase high-frequency AC/DC switch power supply in the prior art. A three-phase power supply 100 together with a DC/DC power supply conversion unit 105 constitutes all application solution of a three-phase two-stage high-frequency switch power supply topological circuit through a three-phase power factor correction unit having a “Vienna” structure and comprising high-frequency inductors 101, diodes 102, triodes 103 and energy-storage capacitors 104. The obvious defects of this solution are as follows: firstly, a specific two-stage high-frequency switch structure reduces the total conversion efficiency of the power supply; secondly, three high-frequency inductors 101 can significantly increase the total cost of the power supply; thirdly, eighteen high-frequency diodes 102 and three high-frequency switch triodes 103 can increase the total cost of the power supply; fourthly, two high-voltage energy-storage capacitors 104 can hinder further improvement of the service life of the power supply; fifthly, a “Vienna” preliminary stage being in power factor correction cannot work in a step-down but only voltage rising manner, and thus an output voltage is over high to bring great processing stress for a subsequent circuit; sixthly, due to existence of high-voltage energy-storage capacitance, electrified initial impact current is extremely large; seventhly, a control loop algorithm strategy of the three-phase high-frequency switch is high in complexity.
FIG. 2 shows another topological circuit application solution of a three-phase high-frequency inversion switch power supply. A three-phase power supply 200, a three-phase power frequency rectification or commutation unit including twelve high-frequency switch triodes 201 and, six high-frequency switch diodes 202, two filter energy-storage capacitors 203 and two DC/DC power supply conversion units 204 constitute a three-phase single-stage high-frequency switch power supply topological circuit, so as to form a three-phase AC/DC application solution, or a DC/AC three-phase application solution, or a three-phase power supply bi-directional converter application solution. However, since there are too many elements in a three-phase power frequency rectification or commutation unit, conduction loss when large current passes is increased, and when a circuit of a DC/DC unit is in a DC/DC converter operating mode, it belongs to a non-return-zero power. DC/DC circuit solution; when the circuit of the DC/DC unit is in an AC/DC transducer operating mode, it belongs to a non-return-zero constant-current power DC/DC circuit solution. However, this non-return-zero circuit solution in the prior art greatly restricts the selection flexibility of the DC/DC topological circuit so that some topological circuits having high conversion efficiencies difficulty take application advantages here.